The present invention relates to methods and apparatus for filling drums with immiscible liquids, especially liquid white phosphorus and water.
Because of its high reactivity, white phosphorus must be handled with caution. In fact, being very oxidizable, it catches fire spontaneously in air so that it is necessary, in order to store it or to transport it, to cover it with an inert liquid such as water.
In order to carry out the filling, especially of metal drums, with liquid white phosphorus, the usual procedure is described below with reference to accompanying FIG. 1.
A first drum F1 is completely filled with hot water W1 (60.degree.) and a second drum F2 is partially filled with a quantity of hot water W2 equivalent to a quantity necessary for covering the phosphorus which will eventually be added to the drum F1.
A funnel G comprising a lateral tubing is fitted onto the bung of the first drum F1 and the drum F2 is connected to the tubing of the funnel via a right-angle pipe P.
A rigid hollow rod R held by an operator B is inserted in the funnel, this hollow rod being connected via a hose (not shown) to a valve of a liquid phosphorus storage vessel, it possible for this valve to be opened or closed by an operator A.
The operator A opens the valve, and the liquid phosphorus LP substantially fills the drum F1 while displacing the hot water from the drum F1 into the drum F2 and this is continued until the drum F2 is completely filled with hot water. This being confirmed by the operator B, the latter gives the order to the operator A to close the valve.
At this stage, the drum F1 is substantially filled with a specified quantity of liquid white phosphorus covered with the quantity of hot water equivalent to the quantity of water originally in the drum F2.
In order to carry out the filling of other drums, a drum F3 is filled with a quantity of hot water W3 equivalent to the quantity of water for covering the phosphorus, and the funnel G is fitted onto the bung of the drum F2. The drum F2 is connected to the drum F3 and the drum F2 is filled with liquid phosphorus as before and so forth.
Having completed the filling operation(s), the drums are allowed to cool for 24 hours in ambient air and then the following operations are carried out.
The procedure is to adjust the quantity of water above the solidified white phosphorus in such a manner as to provide the obligatory safety void of air above the water and the gross weight of the drums. This adjusting is carried out by siphoning out the excess water. The drums are passed one by one onto a weighing machine, and are then closed and subsequently transported one by one by a lift truck to a storage zone.
This procedure has a number of drawbacks. For example, there is some difficulty in controlling the level of water in the "second" drum F2 which runs the risk of causing an overflow of the phosphorus from the drum during filling and consequently the risk of catching fire and burning the operator B. Also poor synchronization between the two operators can lead to the same result.
There is also some difficulty in passing the hollow rod R which is still filled with liquid white phosphorus, from one drum to another without risk of spurting.
Furthermore, various operations such as unscrewing the funnel and screwing it onto each drum, the siphoning, and the passing of the hollow rod from one drum to another with risk of rupturing the hose are manual operations which, not only are dangerous, but also are lengthy and tend to reduce productivity.